The present invention relates to the field of agricultural machinery, more particularly to mowing equipment and machines, especially those designed to be mounted on the rear or front of a tractor, and its object is a mower comprising at least one cutter bar provided with rotary disks with cutters.
Numerous embodiments of mowers of this type are already known in the prior art, in particular from the documents DE 10 2011 016 284 and EP 2 508 061.
In general, the mowing or cutter bars of these mowers comprise:                an elongated hollow casing with an upper wall and a lower wall,        at least one bearing block mounted at the level of an orifice of the upper wall of the casing,        at least one disk integral with a driven support shaft, which is mounted to be guided in rotation in the said bearing block,        at least one cutter, with a radial and freely rotating protrusion, fixed on the said disk, wherein the bearing block or each bearing block is integral with the casing by screw-type fastening means or at least partial cooperation of a male thread and a female thread.        
The support shaft is rigidly assembled in the upper part, outside the casing, with the disk carrying the cutters, and it is integral in the lower part and inside the casing with a toothed pinion or wheel engaging with an element of a gear train driven by the power take-off of the tractor, wherein the bearing block integrates a ball bearing or needle bearing to facilitate rotation of the said shaft.
The cutters in turn are mounted at the level of the ends of fastening strips assembled rigidly on the disk.
In the embodiments of the aforesaid DE and EP documents, the bearing blocks are of modest size, mounted in orifices of small dimension and integral only with the upper wall of the casing.
Such a construction has several major disadvantages.
A bearing block of modest size intrinsically has limited resistance to stresses and impacts. Furthermore, its fastening on the upper wall alone constitutes an additional limitative factor in terms of rigidity and strength of the construction, wherein transmission of forces to the casing are additionally concentrated locally.
Finally, since the opening of the casing receiving the bearing block is also of small size, demounting for the purpose of replacing certain toothed pinions and wheels mounted in the casing makes it necessary to separate the two walls and open the said casing.
As an alternative, under-dimensioning of the said toothed pinions and wheels may be provided, but this entails more complex kinematic chains with more elements.
In addition, in these embodiments, the bearing block is fixed on the upper wall by visible fastening means, which project relative to the casing and are exposed to the outside atmosphere.
Consequently, earth and other debris cluster around these projecting parts, causing alteration of these parts due in particular to the impacts of stones. Such alteration may make it difficult or even impossible to demount the bearing block. In addition, the accumulation of debris may lead to resistance to movement and to greater wear of mobile parts due to friction.
The cutter bar of the Applicant's mower known by the name “OPTIDISC” (registered trademark) and represented in section in FIG. 1 makes it possible to remedy at least some of the aforesaid disadvantages. The same is true for the cutter bar known from document FR 2 840 765 of the Applicant.
In fact, in these cutter bars, the bearing block is of clearly larger dimension and is integrated solidly with both walls by fastener assemblies, each composed of two elements mutually assembled by screwing, wherein stiffening spacers prevent crushing of the casing during tightening and ensure a good distribution of stresses.
In addition, the mounting orifice of the bearing block makes passage of all toothed pinions and wheels easy.
Nevertheless, the fastener assemblies employed in the aforesaid known embodiments of the Applicant comprise nuts and bolts, the threads and screwing zones of which also project beyond the corresponding bearing block and are therefore exposed, as mentioned in the foregoing.
In addition, considering the radial size of the bearing block and therefore the radial spacing of the protruding assemblies of nuts and bolts, these projecting elements prevent the cutters from performing a complete rotation around their axis (these cutters are situated as close as possible to the upper face of the casing). This implies additional wear of the cutter during collisions with obstacles: in fact, after having struck an obstacle, the cutter rebounds from the obstacle then rotates in the opposite direction, sometimes at high speed.
To ensure that they do not damage the mounting strip (a part that is difficult to replace), specific stops must be provided in order to permit damping of the return movement of the cutter when it has encountered an obstacle.
This therefore culminates in a more complex construction and faster wear of the cutters.
Finally, and most importantly, the cutters are unable to execute a rotation of 360°, meaning that they cannot rotate freely.